Pulse Echo Tool Response Denoising for Cement Evaluation
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Solution Overview
Problem
Recent developments in well drilling, such as heavier drilling fluids and lighter cements, reduce the effectiveness of pulse echo tools in measuring cement quality due to signal attenuation, leading to increased noise in acoustic measurements.
Innovation Solution
A system and method that includes a pulse echo tool with a transducer configured to emit acoustic pulses and measure reflected waveforms, and a data processing system to detect changes in casing thickness, estimate the pulse echo tool response, and remove it from measurements to reduce coherent noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the operating frequency of pulse echo tools is reduced to account for signal attenuation from heavier drilling fluids and thicker casings, then the acoustic signal can penetrate deeper, but noise from pulse echo tool electronics and transducer intrinsic noise increases
Solution Approach 1:
The patent extracts and removes the tool response (noise) from the pulse echo measurements by detecting collar positions and subtracting the estimated tool response from the measurements, thereby isolating the desired formation signal from the electronic and transducer noise
Solution Approach 2:
The patent performs preliminary detection of collar positions and estimation of tool response before final measurement analysis, allowing the noise characteristics to be characterized and removed in advance of the actual cement evaluation measurements
2Strength
If heavier drilling fluids and thicker casings are used in well construction, then wellbore strength and structural integrity are improved, but acoustic signal attenuation increases reducing measurement effectiveness
Solution Approach 1:
The patent converts the harmful effect of signal attenuation into a beneficial measurement approach by using the known collar positions as reference points to characterize and remove tool response, thereby compensating for the reduced signal strength caused by heavier drilling fluids and thicker casings
3Adaptability or versatility
If lighter cements with acoustic properties similar to fluids are used in well construction, then cement placement flexibility is improved, but acoustic signal differentiation between cement and formation becomes more difficult
Solution Approach 1:
The patent extracts the tool response component from the measurements using collar-detected references, allowing for more accurate detection of cement characteristics by removing the dominant electronic noise that would otherwise mask the subtle acoustic differences between lighter cement and formation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for more accurate and precise cement quality assessment by reducing coherent noise in pulse echo measurements, improving the ability to determine the solid, liquid, or gas character of the material behind the casing.
Implementation Method 1
the transducer is configured to emit an acoustic pulse toward a casing... the transducer is configured to emit acoustic pulses and obtain pulse echo measurements of reflected waveforms resulting from acoustic interactions
Data Source
AI summary
A method includes performing pulse echo measurements using a pulse echo tool. The method also includes detecting a casing collar using the pulse echo measurements performed by the pulse echo tool. The method further includes estimating a tool response of the pulse echo tool response at the casing collar using one or more processors based on the pulse echo measurement at the casing collar. The method also includes and removing the pulse echo tool response estimation from at least some of the pulse echo measurements not at the casing collar.